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Atomicorp WAF Research Note: CVE-2026-4093
Stored XSS in Drupal 7 Term Reference Tree module (token display templates and term labels)
CVE Details
- Already protected by existing Atomicorp WAF rules
- Protection status: Understanding Atomicorp WAF Protection Status
- CVE: CVE-2026-4093
- Name: Stored XSS in Drupal 7 Term Reference Tree module (token display templates and term labels)
- Severity: Medium
- CVSS: 5.1 (v4.0) (Medium)
- CVSS version: 4.0
- CVSS source: drupal CNA
- CVSS vector:
CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:P/VC:L/VI:L/VA:N/SC:L/SI:L/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X- Attack vector: Network
- Attack complexity: Low
- Attack requirements: None
- Privileges required: Low
- User interaction: Passive
- Vulnerable-system confidentiality: Low
- Vulnerable-system integrity: Low
- Vulnerable-system availability: None
- Subsequent-system confidentiality: Low
- Subsequent-system integrity: Low
- Subsequent-system availability: None
- Scope: X
- CWE: CWE-79 — Improper Neutralization of Input During Web Page Generation (‘Cross-site Scripting’)
- Related CAPEC attack patterns (via MITRE CWE relationships): CAPEC-209 (opens in a new tab) , CAPEC-588 (opens in a new tab) , CAPEC-591 (opens in a new tab) , CAPEC-592 (opens in a new tab) , CAPEC-63 (opens in a new tab) , CAPEC-85 (opens in a new tab)
- Vendor: taxonomy term reference tree widget project
- Vulnerable product: taxonomy term reference tree widget
- CVE published: 2026-05-21
- CVE last modified: 2026-07-23
- Affected versions (NVD configurations):
- taxonomy term reference tree widget: >= 7.x-1.0, < 7.x-1.12
- EPSS: 0.0017; 6.7th percentile (FIRST (opens in a new tab) )
- Latest Update: 2026-09-06
- Selected Rule IDs observed: 333140 , 333141 , 340095
- Matching rules: 3; rules with blocking actions: 3
- Would-block Rule IDs: 333140 , 333141 , 340095
- Request surfaces inspected: JSON request data, Request argument names, Request arguments, Request cookies, Request headers, SOAP request data, XML request data
Technical CPE data
This section lists vulnerable CPE matches retained from the NVD configurations. It supplements the readable affected-product information above.
cpe:2.3:a:taxonomy_term_reference_tree_widget_project:taxonomy_term_reference_tree_widget:*:*:*:*:*:drupal:*:*- Version start (inclusive):
7.x-1.0 - Version end (exclusive):
7.x-1.12 - NVD match criteria ID:
3390651C-0E1A-4B4C-837A-A8740627DFD5
- Version start (inclusive):
Vulnerability Description
In the Drupal 7 Term Reference Tree module, two stored XSS vectors exist in the widget/formatter rendering pipeline.
Vector A (token display templates): When the Token module is enabled and token display templates are configured, attacker-controlled token output (e.g., term description) is rendered without proper sanitization. Any user who can edit the referenced taxonomy terms can inject HTML/JS that executes when the field is rendered.
Vector B (term label rendering): Taxonomy term labels are not properly sanitized before being rendered in the widget, allowing a user with permission to create or edit taxonomy terms to inject scripts into the term name that execute when a form containing the widget is viewed.
Exploit affects versions 7.x-1.x up to and including 7.x-1.11.
Recommended Actions
Maintain the observed Atomicorp protections. Keep your Atomicorp commercial rules current and confirm that the selected observed rules (333140 , 333141 , 340095 ) have not been locally disabled. Atomicorp commercial rules are enabled by default. If you use Atomic WAF, review the applicable policy and rule settings.
Apply the vendor’s remediation. WAF protection is defense in depth and does not replace upgrading or following the affected vendor’s guidance.
- Affected versions: Drupal Term Reference Tree versions through 7.x-1.11.
- No specific CNA/vendor solution or workaround is included in the current CVE Record (opens in a new tab) . Review the vendor’s security advisories and supported-release guidance before making changes.
Validate after changes. Confirm rule updates are current, review WAF events for the affected application, and test application behavior after vendor upgrades, mitigations, or local policy changes.
Research Notes
Atomicorp WAF protections are designed around attack techniques and exploit behaviors, allowing existing protections to apply across multiple vulnerabilities without requiring a unique rule for every CVE.
Public Vulnerability References
- NVD (opens in a new tab)
- CVE Record (opens in a new tab)
- Exploit or technical research: https://d7es.tag1.com/security-advisories/taxonomy-term-reference-tree-widget-moderately-critical-cross-site-scripting (opens in a new tab)
- Exploit or technical research: https://www.herodevs.com/vulnerability-directory/cve-2026-4093 (opens in a new tab)
Test or Research Source
- Source: Atomicorp AI Research Framework
- Tags: cve, derived, waf-probe, xss
Research Note Context
This research note documents exploit-technique analysis associated with this vulnerability and references Atomicorp WAF protections observed during engineering review, testing, or validation activities.
Atomicorp security controls are generally designed to identify and mitigate attack techniques and exploit behaviors rather than individual CVE identifiers. As a result, protections developed for one vulnerability may also apply to related attack variants and future vulnerabilities using similar techniques.
Learn More
Atomicorp develops commercially supported security technologies for web applications, servers, endpoints, workloads, and legacy enterprise platforms.
Organizations interested in protecting systems against exploit techniques associated with vulnerabilities such as this one can learn more about:
- Atomic ModSecurity Rules: commercially maintained WAF rules for ModSecurity deployments, including protections for web attacks, bots, scanners, malware, exploitation attempts, and emerging vulnerability classes.
- Atomic WAF: an enterprise web application firewall with Atomicorp rules, centralized management, reporting, authentication controls, and operational tooling.
- Atomic ModSecurity Integrator: a special licensing option for MSPs, MSSPs, OEMs, VARs, reverse proxy providers, and other integrators who want to incorporate Atomicorp ModSecurity rule technology into their own products or services.
- Atomic OSSEC: an enterprise OSSEC-based intrusion detection, compliance, and security monitoring platform.
- Atomic Protector: workload protection for Linux, web, cloud, data center, and hybrid environments.
For additional information, product evaluations, or technical discussions, visit https://www.atomicorp.com/ or https://modsecurity.io/ (opens in a new tab) .